Intermittent fasting (IF) has quickly become one of the most talked-about wellness trends, and for good reason. At Vitality, we often get questions about whether IF is a healthy strategy for weight loss, longevity, and metabolic health.
Let’s break down what the science says—especially when it comes to how fasting works, what benefits it may offer, and how men and women may respond differently.
What Is Intermittent Fasting?
Intermittent fasting isn’t a diet—it’s a pattern of eating. It involves alternating periods of eating with periods of fasting. Popular versions include:
16:8 method – fast for 16 hours, eat within an 8-hour window
5:2 approach – eat normally five days a week and eat lightly (around 500–600 calories) two non-consecutive days
These approaches allow your body time to rest and reset between meals—and the benefits go beyond the scale.
What Happens in Your Body When You Fast?
During fasting, your body switches from burning sugar to burning fat. This shift activates several powerful processes, including:
Cellular clean-up (called autophagy), where your body removes damaged cells
Improved insulin sensitivity, which helps regulate blood sugar
Reduced inflammation, linked to lower risk of chronic diseases
Better energy metabolism and mental clarity
Does Fasting Affect Men and Women Differently?
Yes, and this is where things get interesting.
For Women:
A recent study found that overweight women who practiced IF experienced improvements in hormone balance. Specifically, they had lower levels of androgens (like testosterone) and higher levels of SHBG (a protein that regulates hormone availability). This can be especially helpful in conditions like PCOS (Jalilolghadr et al., 2022).
What’s not affected? Estrogen, prolactin, or other reproductive hormones—which is reassuring for most women considering IF.
For Men:
In young, healthy men, IF can lead to a temporary drop in testosterone. However, this didn’t seem to affect muscle mass or strength, especially when combined with resistance training (Jalilolghadr et al., 2022). So, for most men, IF remains a safe and effective strategy when used mindfully.
The Bottom Line
Intermittent fasting can be a powerful tool for metabolic health, but like everything in functional medicine, it should be personalised. Women and men may experience different hormonal responses—and we want to protect not just the number on the scale, but your long-term vitality, strength, and energy.
Thinking about trying IF? Let’s talk about your goals, body composition, and what approach fits best for your lifestyle.
References
Jalilolghadr, S., Arefhosseini, S. R., Faghih, S., & Kheirouri, S. (2022). The effect of intermittent fasting on sex hormones and SHBG in overweight or obese premenopausal women: A randomized controlled trial. Journal of Clinical Medicine, 11(12), 3466. https://doi.org/10.3390/jcm11123466
Marinac, C. R., Sears, D. D., Natarajan, L., & Gallo, L. C. (2022). Intermittent fasting in overweight adults: A randomized controlled trial of the 5:2 and 1:1 diets. Nutrition Journal, 21(1), 44. https://doi.org/10.1186/s12937-022-00790-0
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